Among cattle, having horns is a recessive trait. Cattle without horns, which are called polled cattle, are common. Suppose a horned male mated with a polled female. Their offspring are all polled. On maturity, two cattle of the F1 generation mated. Their offspring are a mix of polled and horned cattle.

1. an enzyme is considered a(n) because it speeds up a chemical reaction without being used up.2. in a catalyzed reaction, a reactant is often called a(n) . an enzyme is specific because the shape of its matches only particular reactants.4. an enzyme speeds up reactions by lowering the . the between an active site and its substrate often strains bonds and the reaction proceed.6. a( , which is often a vitamin, binds to an enzyme and plays a role in catalysis.7. high temperatures or changes in ph can an enzyme, causing it to lose its shape and biological activity.